1. Field of the Invention
The present invention relates to an apparatus for use in seismic exploration and more specifically to a seismic source system utilizing a hose bundle for use in marine seismic exploration.
2. Description of Related Art
In the field of marine seismic exploration (surveying), an acoustic signal is generated in a body of water by a source such as an air gun. Typically, several air guns are arranged in spaced relationship to each other. Such arrangement generally is referred to as a subarray. One or more air gun subarrays are towed behind a vessel to perform seismic surveying. In typical operation, one end of a hose bundle (also referred to as an umbilical) is connected to an air gun subarray (one hose bundle per air gun subarray) and the other end of the hose bundle is connected to equipment on the vessel. The hose bundle supplies compressed air and electrical power to the air guns and also provides electrical communication between the air guns and the equipment on the vessel.
A typical prior art hose bundle contains an air hose in the middle of the hose bundle for carrying pressurized air to the air guns. A number of insulated electrical conductors are placed around the air hose for carrying electrical power to the air guns and for providing communication between the air guns and the equipment on the vessel. An outer-shell having armor components and an outer protective jacket is placed around the electrical conductors. Each hose bundle is several hundred feet in length and is normally stored on the vessel by winding the hose bundle on a storage reel which imparts a certain amount of stress on the electrical conductors.
In the prior art hose bundle, the electrical conductors become an integral, non-removable part of the hose bundle during the manufacturing process. Therefore, damaged electrical conductors cannot be removed and/or replaced with new electrical conductors once the hose bundle has been manufactured. To minimize this problem, it is common in the prior art to include spare electrical conductors in the hose bundle. The spare electrical conductors allow for the continued use of the hose bundle even after some of the electrical conductors become damaged and non-operative. The spare electrical conductors, however, are exposed to the same wear conditions as the remaining electrical conductors.
Another problem with the prior art hose bundle is its diameter which affects the overall weight and manufacturing cost of the hose bundle and the operational costs of storing and towing the hose bundle during seismic surveying operations. As previously noted, the hose bundle is typically several hundred feet in length and even a small increase in the diameter of the hose bundle results in a large increase in the overall weight of the hose bundle. The larger diameter of the hose bundle also results in more drag when it is towed behind the vessel during surveying operations. This drag requires the vessel to use more fuel thus increasing operational expenses and also creates additional stress on the hose bundle which can result in a shorter life.
There has been a long felt, yet unsolved need for a more reliable, smaller diameter hose bundle. The present invention provides a hose bundle that addresses the above-noted problems associated with the prior art hose bundles.